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  <title>查找字符串的首次出现</title>

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</div><hr /><div id="function.strstr" class="refentry">
 <div class="refnamediv">
  <h1 class="refname">strstr</h1>
  <p class="verinfo">(PHP 4, PHP 5, PHP 7)</p><p class="refpurpose"><span class="refname">strstr</span> &mdash; <span class="dc-title">查找字符串的首次出现</span></p>

 </div>
 
 <div class="refsect1 description" id="refsect1-function.strstr-description">
  <h3 class="title">说明</h3>
  <div class="methodsynopsis dc-description">
   <span class="type">string</span> <span class="methodname"><strong>strstr</strong></span>
    ( <span class="methodparam"><span class="type">string</span> <code class="parameter">$haystack</code></span>
   , <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <code class="parameter">$needle</code></span>
   [, <span class="methodparam"><span class="type">bool</span> <code class="parameter">$before_needle</code><span class="initializer"> = false</span></span>
  ] )</div>

  <p class="para rdfs-comment">
   返回 <code class="parameter">haystack</code> 字符串从 <code class="parameter">needle</code> 第一次出现的位置开始到 <code class="parameter">haystack</code> 结尾的字符串。
  </p>
  <blockquote class="note"><p><strong class="note">Note</strong>: 
   <p class="para">
    该函数区分大小写。如果想要不区分大小写，请使用 <span class="function"><a href="function.stristr.html" class="function">stristr()</a></span>。
   </p>
  </p></blockquote>
  <blockquote class="note"><p><strong class="note">Note</strong>: 
   <p class="para">
    如果你仅仅想确定 <code class="parameter">needle</code> 是否存在于 <code class="parameter">haystack</code> 中，请使用速度更快、耗费内存更少的 <span class="function"><a href="function.strpos.html" class="function">strpos()</a></span> 函数。
   </p>
  </p></blockquote>
 </div>


 <div class="refsect1 parameters" id="refsect1-function.strstr-parameters">
  <h3 class="title">参数</h3>
  <p class="para">
   <dl>

    
     <dt>
<code class="parameter">haystack</code></dt>

     <dd>

      <p class="para">
       输入字符串。
      </p>
     </dd>

    
    
     <dt>
<code class="parameter">needle</code></dt>

     <dd>

      <p class="para">
       如果 <code class="parameter">needle</code> 不是一个字符串，那么它将被转化为整型并且作为字符的序号来使用。
      </p>
     </dd>

    
    
     <dt>
<code class="parameter">before_needle</code></dt>

     <dd>

      <p class="para">
       若为 <strong><code>TRUE</code></strong>，<span class="function"><strong>strstr()</strong></span> 将返回 <code class="parameter">needle</code> 在 <code class="parameter">haystack</code> 中的位置之前的部分。
      </p>
     </dd>

    
   </dl>

  </p>
 </div>


 <div class="refsect1 returnvalues" id="refsect1-function.strstr-returnvalues">
  <h3 class="title">返回值</h3>
  <p class="para">
   返回字符串的一部分或者 <strong><code>FALSE</code></strong>（如果未发现 <code class="parameter">needle</code>）。
  </p>
 </div>


 <div class="refsect1 changelog" id="refsect1-function.strstr-changelog">
  <h3 class="title">更新日志</h3>
  <p class="para">
   <table class="doctable informaltable">
    
     <thead>
      <tr>
       <th>版本</th>
       <th>说明</th>
      </tr>

     </thead>

     <tbody class="tbody">
      <tr>
       <td>5.3.0</td>
       <td>
        新增可选的 <code class="parameter">before_needle</code> 参数。
       </td>
      </tr>

      <tr>
       <td>4.3.0</td>
       <td>
        <span class="function"><strong>strstr()</strong></span> 成为二进制安全的。
       </td>
      </tr>

     </tbody>
    
   </table>

  </p>
 </div>


 <div class="refsect1 examples" id="refsect1-function.strstr-examples">
  <h3 class="title">范例</h3>
  <p class="para">
   <div class="example" id="example-5328">
    <p><strong>Example #1 <span class="function"><strong>strstr()</strong></span> 范例</strong></p>
    <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br />$email&nbsp;&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #DD0000">'name@example.com'</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$domain&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">strstr</span><span style="color: #007700">(</span><span style="color: #0000BB">$email</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">'@'</span><span style="color: #007700">);<br />echo&nbsp;</span><span style="color: #0000BB">$domain</span><span style="color: #007700">;&nbsp;</span><span style="color: #FF8000">//&nbsp;打印&nbsp;@example.com<br /><br /></span><span style="color: #0000BB">$user&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">strstr</span><span style="color: #007700">(</span><span style="color: #0000BB">$email</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">'@'</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">true</span><span style="color: #007700">);&nbsp;</span><span style="color: #FF8000">//&nbsp;从&nbsp;PHP&nbsp;5.3.0&nbsp;起<br /></span><span style="color: #007700">echo&nbsp;</span><span style="color: #0000BB">$user</span><span style="color: #007700">;&nbsp;</span><span style="color: #FF8000">//&nbsp;打印&nbsp;name<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
    </div>

   </div>
  </p>
 </div>


 <div class="refsect1 seealso" id="refsect1-function.strstr-seealso">
  <h3 class="title">参见</h3>
  <p class="para">
   <ul class="simplelist">
    <li class="member"><span class="function"><a href="function.preg-match.html" class="function" rel="rdfs-seeAlso">preg_match()</a> - 执行一个正则表达式匹配</span></li>
    <li class="member"><span class="function"><a href="function.stristr.html" class="function" rel="rdfs-seeAlso">stristr()</a> - strstr 函数的忽略大小写版本</span></li>
    <li class="member"><span class="function"><a href="function.strpos.html" class="function" rel="rdfs-seeAlso">strpos()</a> - 查找字符串首次出现的位置</span></li>
    <li class="member"><span class="function"><a href="function.strrchr.html" class="function" rel="rdfs-seeAlso">strrchr()</a> - 查找指定字符在字符串中的最后一次出现</span></li>
    <li class="member"><span class="function"><a href="function.substr.html" class="function" rel="rdfs-seeAlso">substr()</a> - 返回字符串的子串</span></li>
   </ul>
  </p>
 </div>


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